Aortoesophageal fistula following thoracic branch endoprosthesis for cryptogenic penetrating aortic ulcer in a patient on pembrolizumab.

Penetrating aortic ulcers are uncommon and life-threatening. We describe the case of a 67-year-old man who presented with fever and chills and was found on computed tomographic scan to have a thoracic penetrating aortic ulcer. The patient underwent placement of a thoracic branch endoprosthesis, with a postoperative course complicated by ileocolic pseudoaneurysm, progressive aortitis, and a fatal aortoesophageal fistula. The management of penetrating aortic ulcer in the setting of multiple confounding factors is discussed in the context of this patient's complex medical presentation, with a focus on the potential role of pembrolizumab in his disease progression.